VMP Performance tests Heatshield Productsâ€™ I-M Shield on its GT350
By Steve Turner
Photos by Steve Turner and courtesy of Heatshield Products
As the factory continues to squeeze more and more performance out of its vehicles the software in the PCM is also quick to reel in the ignition timing in response to heat. Since heat can lead to detonation, this is a wise safeguard. However, for those of us that want maximum performance at all times, keeping the inlet air cooler and the timing more aggressive is a great idea.
During The Roar Before testing preceding the Rolex 24 Hours at Daytona we noted that the Shelby GT350R-C racers featured heat shield material on their airboxes and inlet tubes. That indicated to us that these cars might be sensitive to hot inlet air in extreme situations. When Heatshield Products said it would be testing its I-M Shield intake manifold kit at VMP Performance, we joined in to watch VMPâ€™s Justin Starkey test the product on the company Shelby GT350 project car.
â€œWe see a fair amount of sensitivity to inlet air temps, on both naturally aspirated and supercharged applications,â€ Justin explained. â€œAnything you can do to keep things cooler is good.â€
In preparation for the installation of the I-M Shield, Justin made baseline runs at normal operating temperatures then he ran three back-to-back runs to heatsoak the engine compartment. Both sets of runs were performed with the hood down and no fans in front of the radiator. That is quite the opposite of how cars are usually tested on a static chassis dyno, as cars moving down the road will see more airflow than a fan can replicate.
You check out some of those runs right hereâ€¦
In both instances the runs with the I-M Shield in place showed lower inlet temps as measured at the top of the intake with an infrared thermometer (which is not pure science but a solid indicator that the intake was seeing less heat). The runs starting at normal operating temperatures were about 10 degrees cooler, while the heatsoaked runs were about 5 degrees cooler. The lower temp readings were a good sign, however, in both cases the I-M Shield runs produces more power across the pull, which was the better news.
â€œIt made a little more power than I expected,â€ Justin said of the shielded intake.